olderdan has a soundly designed T&C setup here........
My contribution would be a collet block, 5C and probably 24 stop indexing.

Originally Posted by C-Bag

Do you think 5C is better than R8?

I use 5C in my T&C grinder (which I posted here recently) but that was largely because I used a Spin Indexer to rotate the the tool and that comes bored for 5C. However, the 5C has allowed me to do things which I could not have with R8, due to its through hole and larger available holes.
Both R8 and 5C are limited in that they come in discrete inch or metric sizes, which means that you need a multitude of collets to cover a full range of sizes in small steps. Of course that doesn't matter if you only need to hold the main sizes, but it becomes a problem if, like me, you want to hold drill bits in 1/64" and 0.5mm steps as well as a full range of number and letter sizes. For that I use adjustable collets in an ER25 chuck with 5C stem. You could use a normal drill chuck to cover the size range but without a through hole you are forced into large overhangs.
I have a large number of drill bits with a MT1 shank, the 5C allows me to feed them in from the back which I couldn't do with R8. For anything with a MT2 shank I have made a 5C holder with a MT2 taper inside, this usually leaves a lot of overhang but with care it gets the job done.

Tony Foale's accurate comments triggered email new action in this thread; and of great interest to me. 5C is popular for many applications, and rightly so. Compact OD, with comparative large maximum bore, in more sizes than many realize, being OD threaded operable by a hollow drawbar, AND if selected carefully ID threaded for a variety of stock stops. New, they are available in roughly 4 price ranges.
Tony is correct that a 5C would hold a an ER setup nicely; and useful for tool or workholding as well.
Now for a little more on collets.
All that aside, an enterprising designer could build a replacement/ alternate spindle(s) for a spin-dex carrying ER's; utilizing more of a compression than collapse function. The compression feature permit range of closure of beyond the few thousandths of a 5C. 5C, R8, 2J, 215, etc are split in front only, sized and cylindrical at one particular diameter only. ANY other only pinch, which can also 'spring' the collet into deformity, and unreliable thereafter.
The brand I can't recall; but there was a grinder for larger drills using Jacobs Rubberflex, that also function ala collapse. They're tool steel fingers bonded to neoprene [?] spacers, very good work holding collets. The drawback is they need a handwheel about 10" diameter to operate. Too big for convenient sized T&C abrasives.
Another 5C advantage. Using the largest with an eccentric bushing will grind beautiful, tapered boring bars; the right way.

...... an enterprising designer could build a replacement/ alternate spindle(s) for a spin-dex

Actually, I made another spindle (should a hollow tube be called a spindle??) with a flat flange on the end to fit a small lathe chuck, either 3 or 4 jaw. It is useful. I'll try to remember to take some pix.

I'm sorry if I'm not the first to ask, but is there any way to get set of plans for this? I've looked around the site and couldn't find them. For the first few projects I'm considering after retirement, this one would definitely be in the top 10

I'm sorry if I'm not the first to ask, but is there any way to get set of plans for this? I've looked around the site and couldn't find them. For the first few projects I'm considering after retirement, this one would definitely be in the top 10

Hi tmoore4748. The only plans I have are in Sketchup form, these are 3D and to scale so you can dimension the parts and you are welcome to them if they will be of use to you.
These files are to large for the forum so I would have to send it in zipped form to your email address ( you can PM me if you wish).
Thanks for your interest.
Olderdan

Hi tmoore4748.
These files are to large for the forum so I would have to send it in zipped form to your email address

Alan, you might consider Dropbox. You can get quite a bit of free space and it is convenient to just drop files there and then you only have to pass a coded URL (supplied by Dropbox for each file) on to all whom you wish to see it. It is very easy to use.

I designed this 2" 4 Tool Square Tool Post Turret to overcome some of the short comings of the standard four way tool posts that sometimes come as standard issue on new lathes. My design employs a 3...

I designed this 2-1/2" 4 Tool Square Tool Post Turret to overcome some of the short comings of the standard four way tool posts that sometimes come as standard issue on new lathes. My design employs...